Improvement in bit-stocks



CfL. GRI'SWOLD. Ens-Stock I I I I I I 1 I I I I I I I I I Patented Sept..17. 1878.

III. I

M'bzesses N. PErEas, P ER, WASHINGTON. D C.

UNITED. STATES PATENT OEEIoE.

CHARLES L. GRISWOLD, OF CHESTER, CONNECTICUT, ASSIGNOR OF HALF HIS RIGHTTO HENRY MOTIGHE, OF NEW YORK, N. Y.

IMPROVEMENT IN BIT-STOCKS.

Specification forming part of Letters Patent No. 208,168, datedSeptember 1?, 1878; application filed February 18, 1878.

To all whom it may concern:

Be it known that I, CHARLES L. GRIswoLD, of Chester, in the county ofMiddlesex and State of Connecticut, have invented a new and usefulImprovement in Bit-Stocks; and I do hereby declare that the followingis. a full, clear, and exact description of the same, reference beinghad to the accompanying drawin g, forming part of this specification.

My invention consists in a novel construction and combination, with thesocket portion of a bit-stock or tool-holder, of a thimble, ferrule, orcap for holding a bit or a tool firmly and securely in place in thesocket of the stock or holder, as hereinafter particularly described.

In the accompanying drawings, Figure 1 is a longitudinal sectional viewof a bit-stock embodying my improvement. Fig. 2 is an end view with thebit in cross-section.

Arepresents a portion of the brace or stock, provided with a socket, B,for the reception of the square portion 0 of the shank of a bit, C. Onthe portion of the stock surrounding the socket is a screw-thread, a. Drepresents a thimble or ferrule, fitting over the socket portion of thestock A, and provided with a female thread corresponding with the threada, so that it may be screwed on and ofi. The outer end of the ferrule Dis provided with an opening divided into two parts, e f. The part c islarge enough to allow the ferrule to turn freely around the shank of thebit, but is smaller than the enlarged square portion 0; and the part fforms a notch large enough to permit the square portion'c to pass freelythrough it.

Below the opening 6 is a shoulder, 61, for engagement with the shoulderof the shank c.

In order to attach the bit to the stock the ferrule D is unscrewed aportion of the way, sufficiently to allow the square portion 0 to passthrough the notch f and enter the socket B in an inclined direction, asshown in dotted lines in Fig. 1.

As soon as the end of the shank has entered the socket and its largestportion has cleared the notch f the bit C is moved to an uprightposition, or to a direction extending rectilinearly from the socketportion of the stock, so as to cause the square portion 0 to enterfarther into and fit snugly in the socket B, and the round portion ofthe bit to occupy the opening 6 of the ferrule. The ferrule D is thenscrewed down until its shoulder d presses closely against the shoulderof the shank, shown in full lines, and thus holds the bit firmly andsecurely in place.

To remove the bit it is only necessary to unscrew the ferrule until thebit C can be inclined sufficiently to allow it to be withdrawn from thesocket and drawn through the notch f.

A bit-stock constructed according to this invention is applicable to theholding of bits of any of the usual descriptions. The pressure of theferrule upon the shank is in a di-' rection longitudinally of the bit,instead of laterally, as heretofore, and it is impossible for the bit tobe withdrawn from the socket except by partially unscrewing the ferrule.

The invention is also applicable to tool-holders of variousdescriptions.

Bit-stocks and tool-holders having their socket portions formed withexternal screw threads to fit clampingsleeves, caps, or thimbles havingopenings entirely through their walls, to permit lateralmovementofabitortoo], have heretofore been constructed; but the openings entirelythrough the walls of said sleeves, caps, or thimbles have rendered themliable to spring and inconvenient for handling. WVhile mydevicepossesses all the convenience afforded by the old form for the lateraldisplacement of the bit, my continuous wall of the thimble renders itrigid, so as to hold the bit firmly in an unvarying position, andpresents a convenient surface for the hand in operating said thimble forclamping or releasing the bit.

What I claim as new, and desire to secure by Letters Patent, is-

The combination, with the socket portion of a bit stock or tool-holderhaving formed thereon the male thread a, of a thimble, ferrule, or caphaving a continuous outer curved surface, an interior screw-thread, b,fitted to said male thread, and having also the internal shoulder d forgrasping, and the recess 6 f for permitting the lateral movement of, thetool, substantially as described.

CHARLES L. GRISWOLD.

Witnesses:

- J. W. BATES,

C. J. BATES.

